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Discussion Starter #1
Rebuit a 93 Z28 shortblock with built heads/intake/306 cam/headers/CAI/2.5 exhaust,etc..etc...
I did install a high volume pump, not sure that was the best choice, wishing I would have gone stock.
However, good oil pressure (50psi) cold, but when engine is hot, it can be as low as 7psi at idle..I know that may be
the minimum acceptable oil pressure but really??? It is a new oil pressure sensor as well.
Any thoughts, I really don't feel like pulling the engine back out after I just did all this...
Rebuilt trans with stall, MSD opti and all ignition parts, 1.6 roller tip rockers, NGK TR55 plugs (gapped at .050)
Tried gapping at .035 and lost alot of power, so I am regapping to .050.
 

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Discussion Starter #3
5W-30 full synthetic
 

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You can try a 5w40 which will be thicker at higher temps compared to a 5w30, but all in all, I wouldn't worry to much about it as long as the pressure comes up to a reasonable level (15-20 psi?)at cruising RPM's (1500-2000?).

You might have a bearing clearance a bit wide/loose but as long as your not bypassing oil before it can get to the bearings, you're getting a lot of flow through them which is a good thing. Most of the newer engines run this way intentionally. The newer Duramax's run ~35 psi maximum oil pressure and typically run in the 10's/20's psi.
 

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You said the engine was rebuilt. If that includes all the usual stuff and you're that low at idle, I'd be concerned. What was the bearing clearance at the crank? Were new cam bearings installed? Were they clocked correctly?
 
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